Paradox Interactive announces Sword of Islam, an upcoming DLC pack for Crusader Kings II that will add the ability to play as Muslim rulers in the strategy sequel. They say the DLC and a patch to support it will be released next month:

The DLC will release at the same time as the next hefty patch which adds new features to the game, such as an expansion of the map into Mali-Songhay, differentiation on strong and weak claims, new plot, expanded combat and more.

Sword of Islam enables players to rule as the Muslim lords, delivering a wealth of specific new mechanics distinctive to these rulers, creating a whole new gameplay experience. Laws, marriage, holding, traits , titles and more will work completely differently.